LTO cycle is defined by ICAO.
It covers four modes of engine operation, namely idle, approach, climb out
and take-off, each of which is associated with a specific engine thrust setting
and a time in mode.
LTO cycle from European Environment Agency, European Union Aviation Safety Agency, "European aviation environmental report 2016", Publications Office of the European Union, 2016, https://data.europa.eu/doi/10.2822/385503